1. Field of the Invention
The present invention relates to a process for producing L-glutamic acid by fermentation.
2. Description of the Prior Art
L-glutamic acid, in the form of the monosodium salt, has been used as a seasoning and has previously been produced by a fermentation process in which wild strains or artificial mutants of L-glutamic acid-producing bacteria, especially of the genus Brevibacterium or Corynebacterium, are used.
Currently, various artifical mutants of the genus Brevibacterium or Corynebacterium capable of producing L-glutamic acid are known. Examples of such artificial mutants are mutants requiring L-arginine, L-histidine, pyrimidine, hypoxanthine, glycerol, chemical compounds having a disufide linkage, or an unsaturated fatty acid such as oleic acid (as described in Japanese Published Examined patent application Nos. 507/1967, 508/1967, 509/1967, 27390/1970, 27391/1970, 19632/1975, 33997/1976, 2998/1977, 6233/1978, 6234/1978, and 8798/1978); mutants resistant to chloramphenicol, streptomycin, chlortetracycline, S-(2-aminoethyl)cystein, monofluoracetic acid, fluorocitric acid, ketomalonic acid, .alpha.-amino-.beta.-hydroxyvaleric acid, DL-threonine hydroxamate, 2-amino-3-phosphopropionic acid, 5-aminolevulinic acid, glutamic acid analogues, benzopyrone, naphthoquinone, or 2,6-pyridinedicarboxylic acid or to inhibitors of the bacterial respiratory system such as malonic acid, NaN.sub.3, KCN, sodium arsenite, 2,4-dinitrophenol, hydroxyamine, and guanidine (as described in Japanese Published Unexamined patent application Nos. 4398/1966, 126877/1975, 38088/1977, 89085/1979, 21763/1980, 21764/1980, 124492/1980, 1889/1981, 35981/1981, 39778/1981, and 48890/1981); mutants sensitive to N-palmitoyl glutamic acid, lysozyme, or to a temperature of more than 34.degree. C. (as described in Japanese Published Unexamined patent application Nos. 64486/1975, 32193/1978, 66687/1977, 122794/1979, and 114293/1980); and a mutant having reduced activity with respect to pyruvic acid dehydrogenase (as described in Japanese Published Unexamined patent application No. 21762/1980). However, because of the continued desirability of increased L-glutamic acid production, processes for the increased production of L-glutamic continue to be sought.